:required
A selector that matches any <input>, <select>, or <textarea> element that has the 'required' attribute set. It's often used to show a red asterisk or border on mandatory fields.
Syntax
/* Usage Example */
input:required {
/* Marks the field as mandatory with a red outline */
border-left: 4px solid red;
}
input:required::after{
content: '; *';
color: red;
}:required Browser support
Widely available
Since
2015 96% global usage
This feature is well established and works across many devices and browser versions. It has been available across browsers since 2015.
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